Please include this information when filing a bug report:
herbie shell --seed 2019067
(FPCore (alpha beta i)
:name "Octave 3.8, jcobi/2"
:pre (and (> alpha -1) (> beta -1) (> i 0))
(/ (+ (/ (/ (* (+ alpha beta) (- beta alpha)) (+ (+ alpha beta) (* 2 i))) (+ (+ (+ alpha beta) (* 2 i)) 2.0)) 1.0) 2.0))
| build-list: contract violation expected: exact-nonnegative-integer? given: '(0) | L | C | |
|---|---|---|---|
| build-list | /opt/racket-7.0/collects/racket/private/list.rkt | 296 | 2 |
| debug-print | /data/pavpan/nightlies/herbie/develop/src/debug.rkt | 107 | 0 |
| run-improve43 | /data/pavpan/nightlies/herbie/develop/src/mainloop.rkt | 346 | 0 |
| (unnamed) | /opt/racket-7.0/collects/racket/private/more-scheme.rkt | 261 | 28 |
| run | /opt/racket-7.0/share/pkgs/profile-lib/main.rkt | 39 | 2 |
| profile-thunk16 | /opt/racket-7.0/share/pkgs/profile-lib/main.rkt | 9 | 0 |
| (unnamed) | /opt/racket-7.0/collects/racket/private/more-scheme.rkt | 261 | 28 |